Potential 2016 Democratic presidential candidate Hillary Clinton, about to go on a book tour for her soon-to-be-released memoir, had a private lunch with President Barack Obama on Thursday.

The White House had no details, saying only that "the president enjoyed an informal, private lunch with Secretary Clinton at the White House this afternoon."

Clinton says she has not yet decided whether to seek the Democratic presidential nomination. Her publisher is expected to release her memoir, "Hard Choices," on June 10 about her tenure as Obama's first-term secretary of state.